Oil steadies after big OPEC driven weekly rally

By Devika Krishna Kumar NEW YORK (Reuters) - Oil prices steadied above $51 a barrel on Friday, with Brent crude on track for its biggest weekly rally since 2009, following OPEC's decision to cut crude output in order to rein in a global glut. After the deal was announced on Wednesday, the market's focus now shifts to the implementation and impact of OPEC's first production agreement since 2008, which will be joined by non-OPEC producers. Crude prices on Friday were pressured by data showing oil